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9390
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Logic guides thinking, but it isn't a substitute for it [Rumfitt]
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Full Idea:
Logic is part of a normative theory of thinking, not a substitute for thinking.
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From:
Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13)
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A reaction:
There is some sort of logicians' dream, going back to Leibniz, of a reasoning engine, which accepts propositions and outputs inferences. I agree with this idea. People who excel at logic are often, it seems to me, modest at philosophy.
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15563
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Properties are very abundant (unlike universals), and are used for semantics and higher-order variables [Lewis]
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Full Idea:
Properties are abundant, numbering at least beth-3 for properties of individuals alone; they are suited to serve as semantic values of arbitrarily complex predicates and gerunds, and higher-order variables. (If there are universals, they are sparse).
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From:
David Lewis (Events [1986], II n2)
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A reaction:
To me this is an outrageous hijacking of the notion of property which is needed for explaining the natural world. He seems to be talking about predicates. He wants to leave me with his silly universals - well I don't want them, thank you.
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9389
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Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt]
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Full Idea:
Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept.
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From:
Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)
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A reaction:
I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy.
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13857
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Truth-functional possibilities include the irrelevant, which is a mistake [Edgington]
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Full Idea:
How likely is a fair die landing on an even number to land six? My approach is, assume an even number, so three possibilities, one a six, so 'one third'; the truth-functional approach is it's true if it is not-even or six, so 'two-thirds'.
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From:
Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 3)
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A reaction:
The point is that in the truth-functional approach, if the die lands not-even, then the conditional comes out as true, when she says it should be irrelevant. She seems to be right about this.
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13853
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It is a mistake to think that conditionals are statements about how the world is [Edgington]
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Full Idea:
The mistake philosophers have made, in trying to understand the conditional, is to assume that its function is to make a statement about how the world is (or how other possible worlds are related to it), true or false, as the case may be.
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From:
Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 1)
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A reaction:
'If pigs could fly we would never catch them' may not be about the world, but 'if you press this switch the light comes on' seems to be. Actually even the first one is about the world. I've an inkling that Edgington is wrong about this. Powers!
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13854
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Conditionals express what would be the outcome, given some supposition [Edgington]
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Full Idea:
It is often necessary to suppose (or assume) that some epistemic possibility is true, and to consider what else would be the case, or would be likely to be the case, given this supposition. The conditional expresses the outcome of such thought processes.
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From:
Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 1)
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A reaction:
This is the basic Edgington view. It seems to involve an active thought process, and imagination, rather than being the static semantic relations offered by possible worlds analyses. True conditionals state relationships in the world.
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